The present invention relates to an automatic temperature control valve for automatically adjusting or controlling temperature of fluid passing through a valve body and, more particularly, to an automatic temperature control valve, wherein fluid or gas passing through a valve body is automatically adjusted or controlled using shape-memory alloy, thereby keeping the temperature of the fluid constant.
In general, a valve device controls the flow of fluid by using a valve stem and a handle adapted to depress a valve seat through which the fluid pass. Further, a temperature control device is employed to detect temperature of the fluid passing through the valve seat for a remote control of the fluid temperature.
As shown in FIG. 1, the prior art valve device for keeping the temperature of the fluid constant includes a fluid detecting sensor 103 mounted to a stem 102 of the valve 101 for detecting temperature of the fluid passing through a valve chamber, a transmission member 104 connected to the fluid detecting sensor 103 for transmitting signals therefrom, and a temperature control device 105 for opening and closing fluid passage depending upon the temperature signals from the transmission member 104 in order to keep the fluid at a constant temperature of a predetermined value.
Although the prior art valve device constructed in this manner works well during an initial period of time after an installation process, it experiences malfunction in controlling the temperature after a certain period of time, due to, e.g., aged components or external environmental factors. In addition, in the prior art valve device, the temperature control device is separated from the fluid detecting sensor by a long distance. Further, the prior art valve device is expensive and has a problem in that it""s configuration gives a discomfort in a repair process. Furthermore, since the valve device is manually opened and closed by the handle, it is cumbersome to manipulate the handle.
It is, therefore, a primary object of the invention to provide an automatic temperature control valve wherein fluid passage of a valve body is automatically opened and closed to allow only fluid having a desired temperature to be flown by using shape-memory alloy within the valve body in order to keep the fluid at a constant temperature of a selected value.
In order to achieve the object, the present invention provides a valve body including therein a valve chamber with a predetermined size having at both ends a fluid inlet and a fluid outlet; an expansion and contraction means mounted within the valve chamber of the valve body and expanding and contracting depending upon a variation of fluid temperature with respect to a predetermined value; and a first opening and closing means inserted into the expansion and contraction means for opening and closing fluid passages by moving leftward and rightward within the valve chamber in response to the expansion and contraction of the expansion and contraction means.